Nowadays, with the rapid development of the mobile Internet technology, operators also find that the data traffic is increased in an exponential way. Moreover, 4G LTE achieves always on IP connectivity feature and IP sessions will remain active even for several months from the attachment status to the detachment status.
However, all these factors also creates more charging transactions to the online charging system (OCS), and the network operators need to often extend the capacity of the online charging system to adapt the increasing TPS (transaction per second). In order to extend the capacity of the online charging system, operators will need to install new hardware box, and move some subscriber's account profiles in one hardware box to a new hardware box to offload the current system. This kind of activity is called as “re-homing” in the telecommunication term. During the re-homing period, online charging system is not allowed to handle these subscribers' charging request from the network, and thus the subscriber current on-going long data session will be cut off and new charging session establishment will be rejected. This will greatly impact the end user's experience of accessing data network due to this kind of network maintenance activity.